Figure 2.

Effects of calcium channel and sodium channel inhibitors in piceatannol-produced modulation in (A) APs recorded in current mode and (B) the AP-clamp-elicited inward currents at the same cell under the conditions of using the normal K⁺-containing pipette internal and bath solutions. The AP contour of rat papillary muscle stimulated at 1 Hz was employed as the voltage protocol in AP-clamp study. Cd²⁺ (50 µmol·L⁻¹) was used to block L-type calcium channel, and lidocaine (20 µmol·L⁻¹) to modulate the inactivation state of sodium channel. In the presence of Cd²⁺, piceatannol can prolong APDs (A-b) associated with increasing inward current (B-b), which can be reversed by lidocaine (A-d and B-d).